Question

Find exact value without using calculator.

cos10/sin80

Answer 1

use the relation,
\(\Large \cos (90-x) =\sin x\)

plug in x =80

Answer 2

cos10=0.98
sin80=0.95

so just divide them=1.03

Answer 3

hartnn: Would you mind explaining a bit more? I got values that are not on the pie chart. Thanks.

zaibali: Can't use a calculator. Teacher doesn't allow calculators on test.

Answer 4

oh...sorrey...i get like you write use calculator...thats why i write it....!!!

Answer 5

did you try plugging in x=80 in
the formula i gave ??

what did u get when u put x=80?

Answer 6

I got cos(10)=sin(80)

Answer 7

correct

so cos 10 = sin 80
then cos 10/sin 80 will be ... ?

Answer 8

They have to be the same number but I don't know the cos 10 or sin 80

Answer 9

.-.

if a=b
then
a/b =1

if cos 10 = sin 80
then cos 10/sin 80 =...

Answer 10

you don't even need the actual values of cos 10 or sin 80

Answer 11

Wow I'm so bad at math. I'm sorry for the frustration lol. It wasn't a good idea for me to take trig in the quick paced summer course.

Answer 12

Thank you!

Answer 13

just practice few problems,
then you will be able to solve it properly :)
and welcome ^_^

Answer 14

\[1-\cos ^{2}20-\cos^270\]

sin^2 20 - cos^2 70

sin^2 20 - sin^2 (90-70)

sin^2 20 - sin^2 20

=0?

Answer 15

\(\huge \checkmark \)

Answer 16

Thanks I think I got the hang of it.

Answer 17

ofcourse! trigonometry is easy :)

Answer 18

It is but there are parts where I just get lost since I don't understand what is going on.

Answer 19

that happens, nothing to worry, if you're stuck, just ask! thats why we are here :) to exchange knowledge :)

Answer 20

I'm glad I found this website. Everyone is friendly and very helpful!

Answer 21

we are also glad to have you here :)
\(\Huge \mathcal{\text{Welcome To OpenStudy}\ddot\smile} \)

Answer 22

Thank you and I'm glad to be here :)